Synscan cable extension

[DoctorD]

Hi

Anyone wanting to extend their handset cable on their Skywatcher mount should have a look at this:-

RJ45 Coupler Cat 5e straight: Amazon.co.uk: Electronics

It's an RJ45 back to back coupler - used in conjunction with a standard CAT5 cable you can extend your handset cable.

RJ11 still goes into the mount, coupler on the end of the original cable and CAT5 network cable from coupler to the hand set - works fine with the 3m cable I have and will probably work with longer cables as it's all low power signaling.

Mine was £0.68 delivered!

Along with my video camera, Im getting closer to being able to observe from my armchair (or at least inside my van!)

Clear skies

Paul

[chrisshillito]

works fine with the 3m cable I have and will probably work with longer cables as it's all low power signaling.

The signal levels are just TTL (0-5V - signal "on" threshold at around 2.2V) and are only designed to work over short distances. The more you extend the greater the cable impedance and the lower the signaling levels drop increasing your mount's susceptibility to corruption by interference. Given the mount protocol has no capability for error detection/correction this may be a risk to be avoided. A more robust solution for remote operation is use PC/laptop control and extend the RS232 side of things.

Chris.

[DoctorD]

Hi Chris

You may be right - I can see that noise would affect the signals as the cable got longer.

The problem is I want to be able to use the fine positioning and PAE functions of the handset remotely - I've not found any software that can do this. I can use Carte du Ciel & Stellarium to control the scope with GOTO commands but not do a PAE (I've got a Synscan AZ mount).

Maybe if there was an EQMOD version for the AZ mounts that would do it but I've been unable to find support for t.

I'll let you know how I get on wit the extension when I next get chance to use it in anger.

Clear skies

Paul

[theodoros1978]

Hi Chris,

today i made a 15m straight cable (Cat5e) and works fine with synscan AZ hand controller. No delay, no voltage problems. It works as fast as a short cable used.

regards.

The signal levels are just TTL (0-5V - signal "on" threshold at around 2.2V) and are only designed to work over short distances. The more you extend the greater the cable impedance and the lower the signaling levels drop increasing your mount's susceptibility to corruption by interference. Given the mount protocol has no capability for error detection/correction this may be a risk to be avoided. A more robust solution for remote operation is use PC/laptop control and extend the RS232 side of things.

Chris.